1. Field of the Invention
The present invention relates to a control apparatus for a hybrid vehicle which is able to drive by transmitting the driving force from at least one of an engine that can perform partial cylinder deactivation operation and a motor to the wheels.
2. Description of the Related Art
As disclosed in Japanese Unexamined Patent Application, First Publication No. 11-350995, for example, there is known a hybrid vehicle provided with an engine and a motor as the power source of the vehicle, in which the motor assists the engine as a power source when the vehicle is running.
Furthermore, as an engine of low fuel consumption there is known an engine which freely switches between all cylinders operation in which all the cylinders are operating, and partial cylinder deactivation operation (cylinder deactivation operation) in which one part of the cylinders are deactivated, and by performing cylinder deactivation operation in cases where cylinder deactivation operation is possible, such as when running at a low speed, and so on, an improvement in fuel consumption efficiency is obtained.
However, in the case of using an engine in which partial cylinder deactivation is possible, due to a difference in the output or torque generated under all cylinders operation, and the output or torque generated under cylinder deactivation operation, there is concern that shock will be generated when switching operation between all cylinders operation and cylinder deactivation operation. In order to prevent this, when switching operation between all cylinders operation and cylinder deactivation operation, the difference in output or torque at the time of switching operation is adjusted by controlling the motor.
However, in the case where the output or torque required by the power source according to the depression amount of the accelerator pedal or the like, is larger than the engine output or torque generated under cylinder deactivation operation, conventional technology immediately switches to all cylinders operation. Therefore, an extension of the range in which cylinder deactivation operation is possible is to be desired, in order to obtain a further improvement in fuel consumption efficiency.